1. Technical Field
The present invention relates to methods and apparatus for imaging biologic specimens in general, and to methods and apparatus for fast focus imaging biologic specimens for analysis in particular.
2. Background Information
Historically, biologic fluid samples such as whole blood, urine, cerebrospinal fluid, body cavity fluids, etc. have had their particulate or cellular contents evaluated by smearing a small undiluted amount of the fluid on a slide and evaluating that smear under a manually operated microscope. Different areas of the smear were examined by manipulating the slide in an X-Y plane. Focus was accomplished by altering the position of the slide along the Z-axis relative to the microscope objective. Reasonable results were attainable using these techniques, but they relied heavily upon the technician's experience and technique. Manually examining the various fields of the sample is also labor intensive and therefore not practically feasible for commercial laboratory applications.
Automated apparatus for analyzing biologic fluid samples are known, including some that are adapted to image a sample of biologic fluid quiescently residing within a chamber. To accurately perform an analysis of a sample quiescently residing with a chamber it is necessary to focus the optics of the device at various different heights (e.g., different heights along a Z-axis for a sample chamber disposed within an X-Y axis plane. To efficiently perform such an analysis, it is necessary to provide such focus at different heights in an accurate, rapid manner.